Trayvon Martin told the last person he ever spoke to by phone that a "creepy-ass cracker" was watching him, Rachel Jeantel testified in the Florida trial of George Zimmerman, the neighborhood watchman accused of second-degree murder.

Jeantel, 19, described as a friend of Martin's, said the 17-year-old was walking home during halftime of the NBA All-Star Game on Feb. 26, 2012, when he became unnerved by someone following him, apparently Zimmerman.

Jeantel said she told Martin to run but that he responded that he was almost home.

"I say, 'Trayvon,' and then he said, 'Why are you following me for?'" Jeantel testified today. "And then I heard a hard-breathing man come say, 'What you doing around here?' ... And then I was calling, 'Trayvon, Trayvon.' And then I started to hear a little bit of Trayvon saying, 'Get off, get off.'"

At times during her early testimony with the prosecution, Jeantel dabbed away tears, as did Trayvon Martin's father, Tracey Martin.

Jeantel, seen as a critical prosecution witness, faced a combative cross-examination during which her credibility was repeatedly called into question

During cross-examination, defense attorney Don West tried to dig into the chain of events preceding Martin's death. West asked why Jeantel didn't call law enforcement after the phone died.

"I thought he was going to be OK because he was right by his daddy's house, but his daddy was not home," Jeantel said as Martin's father cried in court.

Tracey Martin eventually reached out to Jeantel after looking at his son's phone log, Jeantel said. She added that she expected law enforcement to reach out to her.

But none did, apparently, until the Florida Department of Law Enforcement contacted her much later.

The defense later moved to impeach Jeantel after accusing her of telling lies under oath, including her whereabouts during Martin's wake.

"Under oath, you created a lie and said you went to hospital?" asked West.

"Yes," responded Jeantel.

She said she lied because she didn't want to see the body.

Jeantel became increasingly agitated during the cross-examination and court ended for the day when she scoffed about having to continue testifying Thursday.

Jeantel's testimony followed testimony from the first witness to say she thought she knew who was screaming for help in the fatal altercation.

Jane Surdyka was in her home on the night Trayvon Martin was shot and killed and said she could hear a "loud, dominant" voice 20 to 30 feet from where she was. She said she opened her window and could "see two people on top of the ground and one on top of the other."

She said she could hear a "boy's voice" crying for help.

Prosecutor Bernie de la Rionda then played Surdyka's emotional 911 call as Sybrina Fulton, Trayvon's mother, and Surdyka dabbed tears from their eyes.

During cross-examination, Surdyka described the altercation and cries for help as a life-or-death struggle.

"It was, as if nothing else, a plea for mercy?" West asked.

"A plea for someone to save them," Surdyka said.

Zimmerman, who has said he was defending himself, has claimed he was the one screaming that night and that he shot and killed the unarmed teenager after Martin repeatedly banged his head on a concrete sidewalk. Prosecutors suggested it was Martin who was screaming.

A second neighbor, Jeannee Manalo, testified that she also heard screams but did not know who was crying for help. But she was the first witness to testify that she saw a man swinging his arms.

"The one on top was moving," Manalo told the court as she made a punch-like gesture.

But Manalo said she did not know who was punching whom.

The testimony followed a key ruling in the trial by Circuit Judge Debra Nelson to allow jurors to hear several non-emergency calls the former neighborhood watch captain made to police well before the encounter with Martin.

Zimmerman is heard asking during the calls for police to come to his subdivision and check on suspicious strangers, often black. The prosecution argued they should be submitted into evidence because they show his mind-set in the days and months leading up to the shooting.

"The defendant made the calls, he created these tapes, he created these situations. He shouldn't complain," prosecutor Richard Mantei said.

Zimmerman's lead defense attorney said the calls were irrelevant and would confuse jurors, but Nelson overruled his objection today.